Copy machine developing apparatus



July 11, 1967 F G WILDE 3,330,195

COPY MACHINE DEVELOPING APPARATUS Filed Sept. 21, 1964 2 Sheets-Sheet lINVENTOR. fecleggbzg [fi /21a July 11, 1967 F. G. WILDE 3,330,195 COPYMACHINE DEVELOPING APPARATUS Filed Sept. 21, 1964 2 Sheets-Sheet 2 I NVEN TOR.

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United States Patent O 3,330,195 COPY MACHINE DEVELOPING APPARATUSFrederick G. Wilde, Rochester, N.Y., assignor toAddressograph-Multigraph Corporation, Charles Bruning Division, MountProspect, Ill., a corporation of Delaware Filed Sept. 21, 1964, Ser. No.397,713 3 Claims. (Cl. 95-89) This invention relates to copy machines ofthe direct contact printing type and more particularly to new andimproved apparatus for developing sensitized material in such machines.

Machines capable of quickly and economically making copies of anoriginal are in constant demand for business establishments and thelike. Of the various types of copy machines in use, the diazo, or directcontact type affords extremely accurate copies at low cost. In such acontact printing process, a photosensitive copy sheet is superimposedover the original and selectively exposed to light and the sensitizedsheet is then developed in a developing chamber by exposure to adeveloping gas, such as ammonia. This invention relates to improvementsin developing chambers.

Conventional copy machines of the direct contact type include adeveloping chamber in the form of a tank open at one side to form anarea where sensitized material is developed by exposure to a developinggas. Guide rollers and driving means draw a copy sheet across theexposure area, and the tank is provided with a supply of ammonia andwater vapor. customarily, ammonia and water vapor is supplied by feedinga water solution of ammonia into an evaporating tray positioned in thetank where a heater near the tray vaporizes the liquid. Anothervariation used in the past is to feed water into the evaporating tray,and to supply anhydrous or dry ammonia to the tank through a suitablepiping arrangement. One type of developing chamber is illustrated anddescribed in my Patent No. 2,909,980, issued Oct. 27, 1959.

Improvements in copy machines and the use of superfast diazo compoundshas greatly reduced the time required to expose copy sheets. Thus itwould be desirable to increase the speed of the developing process aswell and it has been suggested that the developing speed be increased byincreasing the size of the developing tank, however this solution isunsatisfactory due to the disadvantages of the large and expensivedeveloping chamber that would be required. In fact, the inclusion ofstandard sized evaporating trays in conventional developing tanks makesthem of an undesirably large size in view of the demand for compact copymachines.

Additional disadvantages of conventional developing chambers, inaddition to their large size and their slowness, are that they must beused in a level position for proper functioning of the evaporating tray,and that they must be provided with metering valves and synchronizatronequipment to control the input of ammonia and water vapor.

Accordingly, it is an object of the invention to provide a developingchamber for sensitized material in which the above-mentioneddisadvantages are overcome.

It is another object to provide a developing chamber for the extremelyrapid developing of sensitized material.

It is a further object to provide a developing chamber of convenientsmall size.

It is another object to provide a developing chamber that does notrequire an evaporating tray or vaporizing heater, so that levelinstallation is not required.

Briefly, an embodiment of the invention may comprise a developing tankopen on a portion of its surface to form an exposure area for sensitizedmaterial drawn past the area by means of an endless sleeve which servesto seal the tank. A series of spaced guide rollers or the like holds thesensitized material being developed against the endless sleeve. Insidethe tank there is provided means for supplying ammonia or otherdeveloping gas, and although the customary evaporating tray may be used,in

one embodiment of the invention anhydrous ammonia gas is piped directlyinto the tank. A perforated conduit is provided for supplying a streamof steam within the tank, and the conduit is arranged so that the steamis directed past the ammonia supply and impinges upon the sensitizedmaterial at the exposure area. Additionally, a heater may be providedadjacent the perforated conduit to superheat the steam.

Other objects and advantages and a better understanding of the inventionwill appear from the following detailed description in conjunction withthe appended drawings in which:

FIG. 1 is a sectional fragmentary view of a copy machine embodying thepresent invention;

FIG. 2 is an enlarged sectional view of an alternative embodiment of adeveloping chamber in accordance with the invention;

FIG. 3 is a sectional view of the chamber of FIG. 2, taken along theline 33 of FIG. 2; and FIG. 4 is an enlarged elevational view of thesteam conduit of the machine of FIG. 1.

Having reference now to the drawings and particularly to FIG. 1 there isillustrated a copy machine 10 constructed in accordance with the presentinvention. The copy machine 10 is of the diazo or direct contact typeand includes a feeding assembly 12 for supplying an original to becopied and a photosensitive copy sheet 13 to an exposing assembly 14,where they are superimposed and fed onto a transparent drum 16 having asuitable light source 18. After the copy sheet 13 has been exposed it isseparated from the original and from the drum 16 and advanced to adeveloping assembly 20. As the invention relates to the novel developingassembly 20, and since a detailed description of the exposure andfeeding apparatus of the copy machine 10 is available in US. patents ofSherell E. Camp-bell et al., Nos. 3,215,055 and 3,215,056, the remainingstructure of the copy machine 10 will not be further described.

The developing apparatus 20 in accordance with the invention is adaptedto develop the sensitized material associated with the exposed copysheet 13 by exposure of the sensitized material to a developing medium,such as ammonia gas. To this end the developing apparatus 20 includes atank 22 having an opening 24 at one side thereof which serves as anexposure area and is closed by means of an endless belt 26 moving acrossthe tank 22. When a copy sheet 13 is fed to the developing apparatus 20it is engaged by the endless belt 26 and is carried across the exposurearea 24. In order to supply ammonia within the tank 22 an ammonia inputpipe 28 carries anhydrous or dry ammonia gas from a tank or othersuitable source to the interior of the chamber 22.

In accordance with a novel feature of the invention a conduit 30transports steam into the tank 22, and interconnects the tank 22 and asuitable source of steam at a pressure slightly above atmosphericpressure. As may clearly be seen in FIG. 4, the conduit 30 hasperforations 32 along its length arranged so that the steam supplied bythe conduit is directed in a spray or stream as indicated by the wavylines 34. The steam travels past the supply of ammonia and impinges uponthe sensitized copy sheet 13 as it is drawn into the exposure area 24.Perforations 32 may comprise a series of small openings as shown in FIG.4, or alternatively, one or more elongated slots may be provided.

It has been found that the provision of steam in accordance with theinvention greatly increases the effectiveness of the ammonia gasdeveloping process, greatly increasing the developing speed. Possiblereasons for the increase of developing speed are first that the steampreconditions the sensitized material on the copy sheet 13 for rapiddevelopment by increasing its moisture content. Additionally, the streamof steam may envelop the photosensitive material in a narrow layer ofwater vapor. In view of the great affinity of ammonia to water, the flowof ammonia to the sensitized material would thereby be greatlyaccelerated. Another possibility is that the spray of steam travelingpast the supply of ammonia entrains ammonia vapor and transports itefiiciently to the sensitized material. Whether the increasedeffectiveness of the developing process results from one or more of theabove explanations, or from other reasons, experimentation has indicatedthat the supply of steam provided in accordance with the inventiongreatly decreases the time required for development of the sensitizedmaterial.

The tank 22 associated with the developing apparatus is formed of a gasimpermeable material such as sheet metal or the like and includes abottom wall 36 and side Walls 38. The side walls 38 are rolled inwardlyto form annular beads 40 defining the exposure area opening 24, and actas sealing lips cooperating with the endless belt 26 to seal the tank22.

The endless belt 22 is made in conventional manner of rubber or otherflexible material impervious to ammonia and other developing gas, and isdriven at one end by a drive roller 42 mounted upon a driven shaft 44and is supported at the other end by an idler roller 46 mounted upon anidler shaft 48, The belt 26 thus acts as an endless sealing sleeve inengagement with the annular beads 40, and is driven across the exposurearea 24 in the direction indicated by arrows in FIG. 1. The belt 26engages sensitized copy sheets 13 and transports them across theexposure area 24, its speed of travel being suitably regulated in anyknown manner to accomplish the developing process.

Within the tank 22 there is a series of rollers 50 for supporting thecopy sheets 13 in engagement with the belt 26. The rollers 50 aremounted for rotation upon shafts 52, and each of the rollers is providedwith perforations 54 which allow the developing gas to diffuse freelywithin the tank 22. The shafts 52 are mounted for rotation in suitableU-shaped brackets 56.

In connection with this first embodiment of the invention as illustratedin FIG. 1, the customary evaporation tray used in conventionaldeveloping apparatus has been eliminated and the size of the tank 22 isconsiderably smaller than has heretofore been possible. In view of themodern effort to provide more compact copy machines, the reduction insize made possible by the invention is highly desirable. In addition,elimination of the evaporation tray has rendered installation of theapparatus far less critical than for conventional developers since it isnot necessary to level the tank 22 to assure proper fluid distribution.

Thus it can be seen that the embodiment of the invention illustrated inFIG. 1 is a great improvement over conventional developing apparatus,since it is smaller, operates faster, and does not require levelinstallation. However, although this embodiment is useful forincorporation into new copy machines, it would be desirable to obtainsome of the advantages of the invention in previously constructedmachines without the expense of completely replacing the developingapparatus. To this end there is illustrated in FIGS. 2 and 3 anotherembodiment of the invention which represents a conventional developerconverted to embody the invention.

The developing assembly of FIGS. 2 and 3, indicated generally by thenumeral 58, includes a conventionally shaped developing tank 60, havingside walls 62 rolled inwardly to form annular beads 64 and defining anexposure area opening 66. The tank includes a large rear portion 68formed of a bottom wall 70 and inclined wall portions 72 and housing anevaporation tray 74 and a vaporization heater 76. The evaporation tray74 is suspended from the tank 60 by means of brackets 78, and issupplied with a liquid mixture of water and ammonia which is evaporatedin the usual fashion by the heater 76 to supply developing gas while aspace heating element 80 heats the space within the tank. The assembly58 also includes an endless belt 32 and a pair of perforated guiderollers 84, mounted on shafts 86 journaled in U-shaped supports 88.

In accordance with the invention the conventional developing assembly 58may be adapted for high speed operation through the provision of a steamconduit 90 having perforations 92 (FIG. 2) along its length. Theperforated conduit 90 leads from a suitable source of steam at apressure slightly above atmospheric pressure, and is arranged to directa stream or spray of steam, as indicated by the way lines 94, over theevaporation tray 74 and against the copy sheet 13 in the exposure area66.

In order to allow the steam introduced into the tank 60 by the conduit90 to travel freely to the sensitized material, a flexible resilientguide 96 (FIG. 3) may be used in place of one of the guide rollers 84used in conventional developers. The guide 96 may be constructed of anyresilient material which is unaffected by the developing gas and servesto hold the copy sheet 13 against the endless belt 82.

In accordance with another feature of the invention, and as illustratedin FIGS. 2 and 3, a heating element 98 extends parallel with the conduit90 along its length within the tank 60 and serves to superheat the steamcarried by the conduit into the tank. It has been found that thissuperheating operation increases the developing speed, and it should beappreciated that, if desired, a superheating heater might also be usedwith the conduit 30 of the embodiment of the invention illustrated inFIGS. 1 and 4.

Although the embodiment of the invention illustrated in FIGS. 2 and 3does not have the advantage of small size, as does the embodimentillustrated in FIG. 1, nevertheless the embodiment of FIGS. 2 and 3 ishighly useful since it is of prime importance to make existing machines,having slow developing apparatus, suitable for higher speed operation.The provision of the perforated conduit 90 in the conventional developer58 enables the developing speed to be greatly increased. For example, ina device constructed in accordance with the invention the developingspeed was increased from 75 feet per minute to 128 feet per minute.

It has been found that the perforated steam conduit of either embodimentmay be placed outside of the developing tank in a position to direct aspray of steam onto the copy sheets 13 just before they enter thedeveloping tank. When this is done, a significant increase in developingspeed is realized over conventional developers which do not use a sprayof steam. It is believed that this result is due to a pre-conditioningof the moisture content of the sensitized material to be developed.

In devices constructed in accordance with the invention, it was notnecessary to provide metering valves and synchronization equipment forcontrolling the flow of materials to the developing chamber. Inaddition, the control of moisture conditions within the tank fordifferent types of sensitized material may be accomplished in a simplemanner by regulating the flow of steam.

Although the present invention has been described with reference tospecific illustrative embodiments thereof, it should be understood thatnumerous other modifications and embodiments can be devised by thoseskilled in the art that will fall within the spirit and scope of theinvention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. Apparatus for developing light sensitized material exposed in adirect contact printing process having a latent image on one surfacethereof, comprising: a tank having an exposure area, an endless beltdriven across said exposure area for sealing said tank and for drawingsaid sensitized material across said exposure area, a series of spacedguide means within said tank for holding said material against said beltwith the image bearing surface facing away from said belt, means withinface entering the exposure area to direct steam past 15 said developinggas conduit and past said guide means forcibly impinging said imagebearing surface simultaneously with exposure to said developer gas.

2. The apparatus set forth in claim 1, wherein the developing gas is inthe form of anhydrous gas.

3. The apparatus of claim 1 additionally comprising a heater adjacentsaid perforated second conduit for superheating said steam.

References Cited UNITED STATES PATENTS 1,669,066 5/1928 Murck 95941,802,977 4/1931 Langsner 9594 1,953,160 4/1934 Fuke 95--94 2,172,7839/1939 Alink et a1. 96-49 2,895,397 7/1959 Hurlbut 9589 FOREIGN PATENTS664,373 8/ 1938 Germany.

NORTON ANSHER, Primary Examiner. CLIFFORD B. PRICE, Examiner. I F.PETERS, JR., Assistant Examiner.

1. APPARATUS FOR DEVELOPING LIGHT SENSITIZED MATERIAL EXPOSED IN ADIRECT CONTACT PRINTING PROCESS HAVING A LATENT IMAGE ON ONE SURFACETHEREOF, COMPRISING: A TANK HAVING AN EXPOSURE AREA, AN ENDLESS BELTDRIVEN ACROSS SAID EXPOSURE AREA FOR SEALING SAID TANK AND FOR DRAWINGSAID SENSITIZED MATERIAL ACROSS SAID EXPOSURE AREA, A SERIES OF SPACEDGUIDE MEANS WITHIN SAID TANK FOR HOLDING SAID MATERIAL AGAINST SAID BELTWTH THE IMAGE BEARING SURFACE FACING AWAY FROM SAID BELT, MEANS WITHINSAID TANK FOR SUPPLYING DEVELOPING GAS TO SAID EXPOSURE AREA ANDINCLUDING A DEVELOPING GAS SUPPLY CONDUIT ARRANGED ADJACENT THE EXPOSUREAREA TERMINATING WITHIN SAID TANK, A PERFORATED SECOND CONDUIT WITHINSAID TANK FOR SUPPLYING A STREAM OF STEAM AT A PRESSURE SLIGHTLY ABOVEATMOSPHERIC PRESSURE, SAID SECOND CONDUIT BEING IN A POSITIONIMMEDIATELY ADJACENT THE IMAGE BEARING SURFACE ENTERING THE EXPOSUREAREA TO DIRECT STEAM PAST SAID DEVELOPING GAS CONDUIT AND PAST SAIDGUIDE MEANS FORCIBLY IMPINGING SAID IMAGE BEARING SURFACE SIMULTANEOUSLYWITH EXPOSURE TO SAID DEVELOPER GAS.